CVE-2026-87461 in Chrome
Summary
by MITRE • 09/09/2026
Information leak in Core in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to leak cross-origin data via a crafted Chrome extension. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as an information leak within the core components of Google Chrome, specifically affecting versions prior to 153.0.8010.36, represents a significant breach in cross-origin isolation principles. This flaw allows a remote attacker to access sensitive data belonging to other origins through the exploitation of a maliciously crafted Chrome extension. The severity is classified as low by Chromium security standards, yet the implications for user privacy and data integrity remain substantial due to the potential exposure of personal or proprietary information that should be strictly isolated from external scripts and extensions.
At its technical core, this vulnerability stems from an improper implementation of cross-origin resource sharing policies within the browser's extension system. Chrome extensions operate with elevated privileges compared to standard web pages, which is necessary for their functionality but also introduces a larger attack surface if not properly constrained. In this specific instance, the flaw likely involves a failure in the permission model or content script injection mechanisms that inadvertently expose internal state variables, DOM elements, or API responses from one origin to another. When an attacker crafts an extension designed to exploit this misconfiguration, it can bypass the same-origin policy restrictions, effectively reading data such as cookies, local storage contents, or dynamic page content from sites where the user is authenticated and active.
The operational impact of this vulnerability centers on unauthorized data access without direct user interaction beyond installing the malicious extension. Once installed, the extension can silently exfiltrate cross-origin data to a remote server controlled by the attacker. This could lead to session hijacking if authentication tokens are exposed, identity theft through personal information leakage, or corporate espionage if sensitive business documents accessed via web applications are compromised. The low severity rating reflects the complexity required for exploitation and the specific conditions needed, such as user consent to install extensions from untrusted sources, but it does not diminish the potential harm in scenarios where users frequently install third-party tools without rigorous vetting.
Mitigation strategies primarily involve updating Google Chrome to version 153.0.8010.36 or later, which addresses the underlying logic errors in the extension API handling. Users should also adopt strict browsing hygiene by only installing extensions from verified publishers and reviewing permissions requested during installation carefully. From a defensive posture perspective, this incident highlights the importance of enforcing Content Security Policy directives that restrict data exfiltration channels and utilizing browser settings to limit cross-origin access for untrusted scripts. Industry standards such as CWE-200, which covers Information Exposure, categorize this type of flaw under improper restriction of information flow between security domains. Furthermore, in the context of the MITRE ATT&CK framework, this vulnerability aligns with techniques related to Collection and Exfiltration over C2 channels, emphasizing the need for robust endpoint detection and response capabilities that monitor unusual data transfer patterns originating from browser processes.